When it comes to flight, nature just has the edge on engineers. This is according to a study comparing hummingbirds with one of the world’s most advanced micro-helicopters. Researchers found that in terms of the power they require to lift their weight, the best hummingbird was over 20% more efficient than the helicopter. Prof. David Lentink from Stanford University in California explained that the flight performance of a hummingbird, the only bird capable of hovering for a long time, was extremely difficult to measure .“Imagine a 4g bird ,”he said,“ The force they generate is tiny. As a result, the drag of a hummingbird wing has never been measured accurately .”Drag is the force opposing the upward force of lift that birds’ wings generate by flapping. Prof. Lentink and his team wanted to understand if feathered hummingbird wings were more efficient — using less power to overcome drag — than the engineered blades of a helicopter of a similarly tiny scale. He and his colleagues compared the birds’ performance to an advanced micro-drone, a 16g helicopter used for surveillance by British troops in Afghanistan. To make the laboratory measurements, they used wings from hummingbird specimens kept in museums. By putting these detached wings into an apparatus called a wing spinner, the team was able to measure exactly how much flapping power was required to lift the bird’s weight. Prof. Lentink’s colleagues also made recordings of wild hummingbirds in flight, to measure the exact movements of their wings which beat up to 80 times per second.“ By combining the wings’ motion with the drag that we measured in the lab, we were able to calculate the aerodynamic power that hummingbird muscles need to provide to sustain hovering,” explained Prof. Lentink. One species, the Anna’s hummingbird, was the champion hoverer, performing much more efficiently than the helicopter. But on average, the birds’ hovering performance was on par with the helicopter .“This shows that if we design the wings well, we can build drones that hover as efficiently, if not more efficiently, as hummingbirds ,”said Prof. Lentink .“Clearly we are not even close to hummingbirds in many other design metrics, such as wind gust tolerance and visual flight control through clutter, to name a few. ”